The prior art provides a variety of ways and methods to secure an elongated element on an empty spool.
An adhesive tape may be provided on the core of the spool to hold the leading end of the elongated element on the spool.
An alternative is to provide the leading end with a glue, e.g. hot melt.
Still another way is to have spools where either the core or one or both flanges is or are provided with a spring-like clip to hold the leading end of the elongated element.
EP-A1-0 580 228 discloses a spool with a core and where this core has at least one fixing hole. The leading end of the elongated element is plastically bent. A reference mark is provided on the spool to indicate the location of the fixing hole and to facilitate its finding and putting the bent part in the hole.
JP-A-04-016467 discloses a wire winding device to automatically fix a leading end on an empty spool in a winding process. The leading end comprises a bent part. During the start of the winding process, the first windings are wound over the bent part to securely fix the wire on the spool.
All of the above-mentioned ways to secure a leading end of an elongated element to a spool have their disadvantages.
Use of an adhesive tape or of a glue, e.g. a hot melt, may slow down the transfer of an elongated element from one spool to another spool or the fixing of the elongated element on a new spool, e.g. because the hot melt may need some time to harden and the adhesive tape may also need some time to fix before carrying out the first and subsequent windings on a spool.
The use of a clip on the core of the spool or on the flange of the spool complicates the spool configuration and may lead to additional measures for guaranteeing a smooth last phase during unwinding.
Bending the leading end and fixing the bent part in a hole in the core of the spool necessitates sensor means for locating the hole and also slows down the fixing of the elongated element to the new spool.
Regarding the disadvantages of the wire winding device disclosed in JP-A-04-016467, during the unwinding process, the unwinding wire can not be used to its full length since fixing force decreases when unwinding. The wire gradually loses grip on the spool, which may lead to uncontrolled movement of a great length of the wire.